<!DOCTYPE html>
<html lang="zh-CN">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>

<body>
    <script>
        //注意一下flag=true
        function handleData(arr, flag = true) {
            let sum = 0
            for (let i = 0; i < arr.length; i++) {
                sum += arr[i]
            }
            if (flag) {
                return sum
            } else {
                return sum / arr.length
            }
        }
        let re = handleData([1, 4, 6], true)
        console.log(handleData([1, 4, 88]))
        console.log(re);

    </script>
</body>

</html>